Polyoxometalate@copper catalyst for electrocatalytic coupling of halo-(hetero)aromatic hydrocarbons and carbon dioxide for synthesis of (hetero)aromatic acid

Carbon dioxide (CO₂) is an abundant, non-toxic C1 feedstock, while (hetero)aromatic carboxylic acids are crucial structural frameworks and synthetic precursors in organic, materials, and medicinal chemistry. Herein, we report a Polyoxometalate@Copper (SiW₁₂@Cu NPs) catalyst deposited on copper foam (CF) via simple electrodeposition (potential range: 0.6 V to -0.8 V, scan rate: 50 mV·s⁻¹) for the electrocatalytic carboxylation of halo-(hetero)aromatic hydrocarbons with CO₂. The composite electrode leverages the synergistic effects of SiW₁₂ (redox stability, Lewis acidity) and Cu NPs (multivalent states, high conductivity), enhancing electron transfer and CO₂ activation. Under mild reaction conditions (room temperature, 1 atm CO₂, and no noble metals added), this system enables not only arenes but also electron-deficient (hetero)arenes such as halopyridines to undergo direct carboxylation with carbon dioxide, achieving a target product yield of over 65% in merely 40 minutes at a current density of 20 mA. Mechanistic studies confirm substrate electroreduction initiates the reaction, followed by CO₂ fixation. This strategy simplifies drug intermediate modification, avoids structural damage to sensitive molecules, and optimizes drug properties via post-carboxylation, offering sustainable technical support for medicinal chemistry innovation.